1. Field of the Invention
The present invention relates to a radiation image capturing system having a radiation conversion panel for converting a radiation that has passed through a subject into radiation image information.
2. Description of the Related Art
In the medical field, there have widely been used radiation image capturing apparatus which apply a radiation to a subject and guide the radiation that has passed through the subject to a radiation conversion panel, which captures a radiation image from the radiation. Known forms of the radiation conversion panel include a conventional radiation film for recording a radiation image by way of exposure, and a stimulable phosphor panel for storing a radiation energy representing a radiation image in a phosphor and reproducing the radiation image as stimulated light by applying stimulating light to the phosphor. In such a radiation conversion panel, the radiation film with the recorded radiation image is supplied to a developing device to develop the image, or the stimulable phosphor panel is supplied to a reading device to obtain the radiation image as a visible image.
In the operating room or the like, it is necessary to read out and display a recorded radiation image immediately from a radiation conversion panel after the radiation image is captured for the purpose of quickly and appropriately treating the patient. As a radiation conversion panel which meets such a requirement, there has been developed a radiation detector having a solid-state detector for converting a radiation directly into an electric signal or converting a radiation into visible light with a scintillator and then converting the visible light into an electric signal to read out a detected radiation image.
Such a radiation image capturing system is disclosed in Japanese Laid-Open Patent Publication No. 2007-037837, for example. In the disclosed radiation image capturing system, a radiation source for radiating X-rays is disposed above a subject lying on a lying table, and an X-ray image receiver is disposed below an affected part of the subject. X-rays emitted from the radiation source pass through the affected part of the subject, and detected by the X-ray image receiver, which converts the X-rays into an electric image signal.
In the radiation image capturing system, the X-ray image receiver has an image capturing surface which needs to be disposed in facing relation to the radiation source and the subject that are positioned upwardly of the X-ray image receiver. However, when the X-ray image receiver is positioned in alignment with the affected part of the subject, the X-ray image receiver may not be properly positioned in head-on alignment with the radiation source. If an image capturing cycle is carried out while the X-ray image receiver is not facing the radiation source head-on, then the X-ray image receiver is unable to capture a radiation image of the affected part of the subject. Therefore, it is necessary to reset the X-ray image receiver in a desired position and then to perform an image capturing cycle. As a result, the efficiency of the process of capturing a radiation image of the affected part of the subject is relatively low.